import java.awt.*;
import java.applet.*;

public class Histogram extends Applet
{
  private int WIDTH, HEIGHT;
  private Image offScreenImage;
  private Graphics offScreenGraphics;

  public void init()
  {
    Dimension dim = getSize();
    WIDTH = dim.width;
    HEIGHT = dim.height;
  }
  
  public void drawHistogram(String dataString)
  {
    drawHistogram(dataString.split("\\s+"));
  }

  public void drawHistogram(String[] data)
  { 
    if (data.length > 1) {
      offScreenImage = createImage(WIDTH, HEIGHT);
      offScreenGraphics = offScreenImage.getGraphics();

      int maxValue = 0;
      for (int i = 0; i < data.length; i+=2) {
        int nextValue = Integer.parseInt(data[i+1]);
        if (nextValue > maxValue) {
          maxValue = nextValue;
        }
      }

      int barHeight = (int)(2.0*HEIGHT/data.length);
      double widthFactor = (double)WIDTH/maxValue;
      
      for (int i = 0; i < data.length; i+=2) {
        int barWidth = (int)(Integer.parseInt(data[i+1]) * widthFactor);
        
        offScreenGraphics.setColor(Color.yellow);
        offScreenGraphics.fillRect(0, barHeight*i/2, barWidth, barHeight);
        offScreenGraphics.setColor(Color.black);
        offScreenGraphics.drawRect(0, barHeight*i/2, barWidth, barHeight);
        offScreenGraphics.drawString(data[i]+" ("+data[i+1]+")",
                                     4, (i+1)*barHeight/2); 
      }

      paint(getGraphics());
    }
  }

  public void paint(Graphics g)
  {
    g.drawImage(offScreenImage, 0, 0, null);
  }
}